Transmission shift control mechanism

Abstract

A shift control mechanism particularly adapted for use with a manual transmission having a main control shaft on an axis normal to a single shift fork rail. Both rotational and longitudinal motion is transferred from the main control shaft to the shift fork rail through a single pivoted idler lever. A pair of shift forks and a reverse gear transfer bar are connected to an interlock system which insures that the shift fork rail establishes only one gear ratio at any time as it is rotated for crossover selection and moved longitudinally for gear engagement.

What is claimed is: 
     
       1. A transmission shift control mechanism comprising a control shaft rotatable on and slidable along a first axis, an idler lever slidable along a second axis in response to rotation of said control shaft, said idler lever being pivotal about said second axis in response to sliding of said control shaft, a shift rail rotatable on a third axis in response to sliding of said idler lever, said shift rail being slidable along said third axis in response to pivoting of said idler lever, each axis being substantially normal to the other two axes, and means responsive to rotation and sliding of said shift rail respectively for selecting and engaging at least one transmission ratio. 
     
     
       2. The invention of claim 1, further comprising means for limiting said rotation of said shift rail in at least one direction. 
     
     
       3. The invention of claim 1, said control shaft including a control head, said idler lever including first and second lever arms, said control head and said first lever arm defining a first articulated connection, said shift rail including a shift head, and said second lever arm and said shift head defining a second articulated connection. 
     
     
       4. The invention of claim 3, said first and second connections being located at different distances respectively from said first and third axes. 
     
     
       5. The invention of claim 4, said first connection being farther from said first axis than said second connection is from said third axis. 
     
     
       6. The invention of claim 4, said first and second lever arms being of different lengths. 
     
     
       7. The invention of claim 4, said control and shift heads being of different lengths. 
     
     
       8. The invention of claim 6, said control and shift heads being of different lengths. 
     
     
       9. The invention of claim 5, said control head being longer than said shift head. 
     
     
       10. The invention of claim 9, said first lever arm being longer than said second lever arm. 
     
     
       11. The invention of claim 10, further comprising means for limiting said rotation of said shift rail in at least one direction. 
     
     
       12. The invention of claim 11, said limiting means limiting said rotation of said shift rail in two directions. 
     
     
       13. The invention of claim 11, said limiting means limiting said sliding of said idler lever in at least one direction so as to limit said rotation of said shift rail in at least one direction. 
     
     
       14. The invention of claim 12, said limiting means limiting said sliding of said idler lever in two directions so as to limit said rotation of said shift rail in two directions. 
     
     
       15. A transmission shift control mechanism comprising control means movable in a plurality of directions, idler means connected with said control means for articulated movement in one direction relative thereto upon movement thereof in one direction and for articulated movement in another direction relative thereto upon movement thereof in another direction, shift means connected with said idler means for articulated movement in a first direction relative thereto upon movement thereof in its one direction and for articulated movement in a second direction relative thereto upon movement thereof in its other direction, said movements of said control, idler and shift means being respectively on and along first, second and third axes, each axis being oriented transversely relative to the other two axes. 
     
     
       16. The invention of claim 15, wherein each axis is substantially perpendicular to the other two axes. 
     
     
       17. The invention of claim 15, wherein said movement of said control means in its one direction is rotational and said movement thereof in its other direction is longitudinal. 
     
     
       18. The invention of claim 17, wherein said movement of said idler means in its one direction is longitudinal and said movement thereof in its other direction is rotational. 
     
     
       19. The invention of claim 18, wherein said movement of said shift means in said first direction is rotational and said movement thereof in said second direction is longitudinal. 
     
     
       20. The invention of claim 19, said control means being rotatable in a first plane and slidable on said first axis, said idler means being rotatable in a second plane and slidable on said second axis, and said shift means being rotatable in a third plane and slidable on said third axis. 
     
     
       21. The invention of claim 20, each of said planes being oriented transversely relative to the other two planes. 
     
     
       22. The invention of claim 21, each of said planes being substantially perpendicular to the other two planes. 
     
     
       23. The invention of claim 20, each of said axes being oriented transversely relative to the other two axes. 
     
     
       24. The invention of claim 23, each axis being substantially perpendicular to the other two axes. 
     
     
       25. In a transmission including a plurality of gears for establishing a plurality of gear ratios, and means for selecting and engaging gears to establish said ratios; the improvement wherein said selecting and engaging means comprises a control shaft supported for rotation on and axial movement along a first axis, a control head secure to said control shaft for rotation and axial movement therewith, said control head defining a first socket, an idler lever supported for rotation on and axial movement along a second axis substantially perpendicular to said first axis, said idler lever including a first lever arm having a first ball seated in said first socket and forming therewith a first articulated connection, a shift rail supported for rotation on and axial movement along a third axis substantially perpendicular to said first and second axes, a shift head secured to said shift rail for rotation and axial movement therewith, said shift head defining a second socket, said idler lever including a second lever arm having a second ball seated in said second socket and forming therewith a second articulated connection, a selector head secured to said shift rail for rotation and axial movement therewith, a plurality of movable bars, each bar defining a notch in alignment with said selector head, and means responsive to movement of said bars for engaging gears to establish said ratios, said selector head being selectively rotatable into said notches for selecting one of said bars, and said selector head being selectively axially movable in at least one direction for moving the selected bar, thereby effecting engagement of gears to establish at least one of said ratios. 
     
     
       26. The invention of claim 25, said selecting and engaging means further comprising means for preventing movement of the remainder of said bars upon selection of one of said bars by said selector head. 
     
     
       27. The invention of claim 25, wherein one of said bars is a transfer bar defining a slot, and said gear engaging means includes a fixed fulcrum extending into said slot, said transfer bar being movable relative to said fulcrum, a lever supported for pivotal movement about said fulcrum in response to movement of said transfer bar for effecting engagement of gears to establish one of said ratios, and means for preventing axial movement of said selector head in one axial direction when said transfer bar is selected by said selector head, said preventing means allowing axial movement thereof in the other axial direction. 
     
     
       28. The invention of claim 25, wherein said first connection is farther from said first axis than said second connection is from said third axis. 
     
     
       29. The invention of claim 28, wherein said first lever arm is longer than said second lever arm. 
     
     
       30. The invention of claim 28, wherein said control head is longer than said shift head. 
     
     
       31. The invention of claim 29, wherein said control head is longer than said shift head. 
     
     
       32. In a transmission including housing means, and first and second gears supported for rotation in said housing means; the improvement comprising an inwardly opening bore defined by said housing means, a support block rigidly secured to the interior of said housing means and defining another bore, a shaft rigidly supported in said bores, an idler gear defining a groove, said idler gear being slidable on said shaft between a disengaged position and an engaged position in meshing relationship with said first and second gears, and actuating linkage including a transfer bar defining a slot and a notch, a fulcrum pin rigidly secured to the interior of said housing means and extending into said slot, said transfer bar being slidable relative to said fulcrum pin between first and second positions, and an idler lever pivotal about said fulcrum pin, said idler lever including a pad extending into said notch whereby said idler lever is pivoted about said fulcrum pin upon sliding of said transfer bar relative to said fulcrum pin, said idler lever also including a pad extending into said groove whereby said gear is slid between its disengaged and engaged positions upon pivoting of said idler lever about said fulcrum pin.